Hot-air duct for furnaces



(No Model.) 2 Sheets--Sheet 1.

RB. DEWEY.

HOT AIR DUCT FOR FURNACES.

Patented-Aug. 30

R my r MW UNITED STATES PATENT OFFICE.

HOSEA B. DEWEY, 0E MILWAUKEE, WISCONSIN.

HOT-AIR DUCT FOR FURNACES.

SPECIFICATION forming part of Letters Patent No. 369,169, dated August30, 1887.

- Application filed March 17, 1886. Serial No. 195,506. (No model.)

To all whom it may concern:

Be it known that I, HOSEA B. DEWEY, of Milwaukee, in .the county ofMilwaukee and State of Wisconsin, have invented new and usefulImprovements in Hot-Air Ducts for Furnaces; and I do hereby declare thefollowing to be a full, clear, and exact description of said invention,reference being had to the accompanying drawings, and to the letters orfigures of reference marked thereonpvhich form a part of thisspecification.

My invention relates to improvements in hot-air flues for furnaces; andit consists in providing the several sections of flues of the ordinaryconstruction, which lead from the furnace through the walls of thebuilding between the lath to the several apartments to be heated, withan exterior corrugated wall, the interior bends of the corrugations ofthe exterior wall bearing against the exterior of said flues, and theexterior bends being adapted to bear against the lath and studs of thesurrounding wall through which said fiues pass. The objects of saidexterior wall are twofold: first, to serve as a protecting shield aroundthe hot-air flue, whereby the same is prevented from being jammed orbroken by contact with the timbers of the building, and also by whichthe combustible material of the wall is prevented from coming in contactwith and being ignited by the hot-air flue, while the spaces betweensaid corrugations permit of the plaster entering through and clinchingupon the inside between the lath and said shield; second, to provide anair-space between said interior hot-air flue and the outer bend of saidexterior wall,which prevents the points of contact of said exterior wallfrom becoming heated to such a temperature as would endanger thebuilding.

The construction of my improvements are explained by reference to theaccompanying drawings, in which- Figure 1 represents a side View of myimproved flue in connection with a furnace and surrounding wall, thelath and plaster being partially broken away to disclose the flue. Fig.2 represents a horizontal section of the flue and surrounding wall,showing the lath and studding in contact with the exterior bends of theouter wall of the flue. Fig. 3 represents a perspective view of a seriesof sections joined together.

Like parts are represented by the same ref erence-letters throughout theseveral views.

A represents the series of interior hot-air flues through which the hotair passes from the furnace to the rooms to be heated.

B is the corrugated sheet-metal exterior Wall, which surrounds saidseries of dues A. The corrugations of the exterior B extendlongitudinally from one end of the several sections to the other, thuspermitting said exterior to readily conform to the surface of the due A.The inward bends, G, of the corrugations bear against the exteriorsurface of the inner fine, A, and said exterior is attached at suchpoints of contact to the surface of the flue A by rivets or solder, asdesired. The outer bend, D, of the corrugations form a bearing-surfacefor the surrounding Walls and timbers, and,owing to their archedshape,.they add great strength to the flue,which prevents it from beingeither bent or jammed by any ordinary pressure which may be brought tobear against it by the lath or timbers of the inclosing-wall.

By the outward bends of the corrugations a series of air-spaces, E, isformed around the inner flue for the passage of cold air between theinner flue, A, and the apex of such corrugations, whereby that part ofthe exterior wall which is liable to be brought in contact with the lathor studs of the wall, as shown in Fig. 2, is prevented from becomingheated, except only to the low and safe degree of heat.

In fiues as heretofore constructed having a smooth even surface whichbears against the inner surface of the lath of the surrounding wall suchsmooth surface prevents the plaster of the wall (which is usually laidon after the dues are in place) from entering through be-' tween thelath and clinching, as it should, upon the inside, and the plaster whenthus laid against the smooth surface of a flue is liable to become looseand drop off.

It is obvious that with my improved form of flue when inserted in thewall, as shown in Figs. 1 and 2, the corrugations in the flue affordample space for the plaster to enter between them and clinch up theinside of the latch.

Having thus described my invention, what I being adapted to bear againstthe surrounding claim as new, and desire to secure by Letters wall G,substantially as and for the purpose Patent, is specified.

The combination, with the furnace F and In testimony whereofI afiix mysignature in 5 with the wall of the building G, of the interior presenceof two witnesses.

hot-air flue or duct, A, and the corrugated ex g terior wall or bearing,B, the inwardly-pro- HOSDA jeeting bends O of the corrugations being se-\Vitnesses: cured against the interior flue, A, and the out- J AS. 13.ERWIN, IO ward]y-projecting bends of said corrugations C. T. BENEDICT.

